Nitrogen-sparing effect of fat emulsion compared with glucose in the postoperative period

The investigation was directed towards elucidating two questions of current interest in parenteral nutrition: (1) Is it at all possible to obtain positive nitrogen balance during the immediate postoperative course (the "catabolic phase")? (2) Is there any difference in the nitrogen balance if the main energy source consists of hypertonic carbohydrate solution or of fat emulsion? Nine patients were examined during the first six postoperative days after gastric resection with regard to nitrogen balance. All of them were given crystalline amino acids (Vamin) corresponding to 0.3 g N/kg body-weight and day together with fructose, electrolytes, and vitamins. Five of the patients were also given 50 kcal/kg body-weight and day mainly as fat emulsion (Intralipid) and the other four received the same amount of energy mainly as 54 percent glucose solution. The investigation showed that it was possible to obtain nitrogen equilibrium during the immediate postoperative course, whether the main non-protein supply consisted of hypertonic carbohydrate solution or of fat emulsion. There was no significant difference between the two energy sources in this respect. Fat emulsion as main energy source is preferable, however, for several reasons.